https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113495
--- Comment #33 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Pan Li <pa...@gcc.gnu.org>: https://gcc.gnu.org/g:9dd10de15b183f7b662905e1383fdc3a08755f2e commit r14-8639-g9dd10de15b183f7b662905e1383fdc3a08755f2e Author: Juzhe-Zhong <juzhe.zh...@rivai.ai> Date: Mon Jan 29 19:32:02 2024 +0800 RISC-V: Fix VSETLV PASS compile-time issue The compile time issue was discovered in SPEC 2017 wrf: Use time and -ftime-report to analyze the profile data of SPEC 2017 wrf compilation . Before this patch (Lazy vsetvl): scheduling : 121.89 ( 15%) 0.53 ( 11%) 122.72 ( 15%) 13M ( 1%) machine dep reorg : 424.61 ( 53%) 1.84 ( 37%) 427.44 ( 53%) 5290k ( 0%) real 13m27.074s user 13m19.539s sys 0m5.180s Simple vsetvl: machine dep reorg : 0.10 ( 0%) 0.00 ( 0%) 0.11 ( 0%) 4138k ( 0%) real 6m5.780s user 6m2.396s sys 0m2.373s The machine dep reorg is the compile time of VSETVL PASS (424 seconds) which counts 53% of the compilation time, spends much more time than scheduling. After investigation, the critical patch of VSETVL pass is compute_lcm_local_properties which is called every iteration of phase 2 (earliest fusion) and phase 3 (global lcm). This patch optimized the codes of compute_lcm_local_properties to reduce the compilation time. After this patch: scheduling : 117.51 ( 27%) 0.21 ( 6%) 118.04 ( 27%) 13M ( 1%) machine dep reorg : 80.13 ( 18%) 0.91 ( 26%) 81.26 ( 18%) 5290k ( 0%) real 7m25.374s user 7m20.116s sys 0m3.795s The optimization of this patch is very obvious, lazy VSETVL PASS: 424s (53%) -> 80s (18%) which spend less time than scheduling. Tested on both RV32 and RV64 no regression. Ok for trunk ? PR target/113495 gcc/ChangeLog: * config/riscv/riscv-vsetvl.cc (extract_single_source): Remove. (pre_vsetvl::compute_vsetvl_def_data): Fix compile time issue. (pre_vsetvl::compute_transparent): New function. (pre_vsetvl::compute_lcm_local_properties): Fix compile time time issue.
